A computer program, based on the X11 window system operating in a UNIX environment, is developed for processing digital images of dental radiographs. It utilizes algorithms for warping and subtracting serial digital images by the use of reference points identified on the two images, and contains features for correction of film contrast differences. Regions of interest which include the interproximal areas of the teeth are defined with the cursor and analyzed by the program. This program is useful in the study of the change in the alveolar bone density and attachment level of teeth, and may provide a valuable tool in the study of the natural history of periodontal diseases, and the study of bone porosity.